From: Marc <marvin24@gmx.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: clock skew on B/W G3
Date: Wed, 5 Oct 2005 08:34:35 +0200 [thread overview]
Message-ID: <200510050834.35493.marvin24@gmx.de> (raw)
In-Reply-To: <1128464094.6417.31.camel@gaston>
Hi Ben,=20
Le Mittwoch 05 Oktober 2005 00:14, Benjamin Herrenschmidt a =C3=A9crit :
> The problem is indeed in via_calibrate_decr(). This routine works on
> HZ/100 so it will not do any good with HZ not beeing a multiple of 100.
>
> Can you test this patch ?
I can confirm that this patch solves the timer skew on my mac.
Thanks!
>
> Index: linux-work/arch/ppc/platforms/pmac_time.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- linux-work.orig/arch/ppc/platforms/pmac_time.c 2005-09-22
> 14:06:18.000000000 +1000 +++
> linux-work/arch/ppc/platforms/pmac_time.c 2005-10-05 08:14:17.000000000
> +1000 @@ -195,7 +195,7 @@
> ;
> dend =3D get_dec();
>
> - tb_ticks_per_jiffy =3D (dstart - dend) / (6 * (HZ/100));
> + tb_ticks_per_jiffy =3D (dstart - dend) / ((6 * HZ)/100);
> tb_to_us =3D mulhwu_scale_factor(dstart - dend, 60000);
>
> printk(KERN_INFO "via_calibrate_decr: ticks per jiffy =3D %u (%u ticks)=
\n",
>
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
WARNING: multiple messages have this Message-ID (diff)
From: Marc <marvin24@gmx.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rune Torgersen <runet@innovsys.com>,
linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: clock skew on B/W G3
Date: Wed, 5 Oct 2005 08:34:35 +0200 [thread overview]
Message-ID: <200510050834.35493.marvin24@gmx.de> (raw)
In-Reply-To: <1128464094.6417.31.camel@gaston>
Hi Ben,
Le Mittwoch 05 Oktober 2005 00:14, Benjamin Herrenschmidt a écrit :
> The problem is indeed in via_calibrate_decr(). This routine works on
> HZ/100 so it will not do any good with HZ not beeing a multiple of 100.
>
> Can you test this patch ?
I can confirm that this patch solves the timer skew on my mac.
Thanks!
>
> Index: linux-work/arch/ppc/platforms/pmac_time.c
> ===================================================================
> --- linux-work.orig/arch/ppc/platforms/pmac_time.c 2005-09-22
> 14:06:18.000000000 +1000 +++
> linux-work/arch/ppc/platforms/pmac_time.c 2005-10-05 08:14:17.000000000
> +1000 @@ -195,7 +195,7 @@
> ;
> dend = get_dec();
>
> - tb_ticks_per_jiffy = (dstart - dend) / (6 * (HZ/100));
> + tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
> tb_to_us = mulhwu_scale_factor(dstart - dend, 60000);
>
> printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",
>
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
next prev parent reply other threads:[~2005-10-05 6:34 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-03 14:18 clock skew on B/W G3 Rune Torgersen
2005-10-03 14:18 ` Rune Torgersen
2005-10-04 6:14 ` Marc
2005-10-04 6:14 ` Marc
2005-10-04 22:10 ` Benjamin Herrenschmidt
2005-10-04 22:10 ` Benjamin Herrenschmidt
2005-10-04 22:14 ` Benjamin Herrenschmidt
2005-10-04 22:14 ` Benjamin Herrenschmidt
2005-10-05 6:34 ` Marc [this message]
2005-10-05 6:34 ` Marc
2005-10-04 12:48 ` Paul Mackerras
2005-10-04 12:48 ` Paul Mackerras
-- strict thread matches above, loose matches on Subject: below --
2005-10-04 19:22 Rune Torgersen
2005-10-04 19:22 ` Rune Torgersen
2005-10-04 15:15 Rune Torgersen
2005-10-04 15:15 ` Rune Torgersen
2005-10-04 19:14 ` George Anzinger
2005-10-04 19:14 ` George Anzinger
2005-10-01 12:29 marvin24
2005-10-02 16:46 ` Marc
2005-10-02 16:46 ` Marc
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